Bulletin of the Korean Chemical Society最新文献

Mechanochemical reactions are chemical processes induced by mechanical energy. Unlike solution-based reactions, a key advantage of mechanochemistry is that reactions can be carried out without solvents. This feature, coupled with its simplicity and sustainability, makes mechanochemistry an increasingly powerful tool for material synthesis. However, traditional mechanochemical reactions typically rely on electronic ball milling devices, which can limit temperature control. Recent studies are exploring ways to selectively synthesize desired compounds using grinding techniques with highly reactive molecular precursors. In this Account, we highlight several examples of manual grinding mechanochemical reactions, demonstrating that solid-state grinding alone can achieve high yields and selectivities. This grinding approach, which uses highly reactive and stable ionic solids as starting materials, opens new possibilities for solid-state reactivity that were previously unattainable with conventional ball milling methods.

Designing a moderate band gap is sometimes intentionally chosen. When the donor polymer has a deeper HOMO level, a higher Voc can be gained which boosts total PCE in organic photovoltaics (OPVs) (Liao et al., Joule 2020, 4(1), 189–206; Mamba et al., J. Phys. Chem. A 2021, 125(50), 10593–10603; Choi and Jo, Org. Electron. 2013, 14(6), 1621–1628; Jo et al., Org. Electron. 2012, 13(10), 2185–2191). This is crucial in DPP-based copolymer frameworks, which frequently have short band gaps and may experience poor Voc. Since DPP is a low bandgap due to strong-acceptor, thus, modifying it with weak donor units can raise the bandgap and lower the HOMO to make it suitable for multi-junctions or higher Voc. We report the synthesis, properties, and photovoltaic applications of a donor-acceptor (D-A) conjugated copolymer based on diketopyrrolopyrrole (DPP) and biphenyl, namely PDDPPhenyl. This polymer exhibits broad absorption ranging from 400 to 900 nm with a band gap of 1.59 eV. As expected, a low HOMO level of −5.29 was gained by introducing biphenyl as a weaker donor. The optimized weight ratio goes to 1:4 for PDPPPhenyl:PC₇₁BM with 3.8% PCE.

Ornithine decarboxylase (ODC) is a critical enzyme in the polyamine biosynthesis pathway that catalyzes the conversion of l-ornithine to putrescine using pyridoxal 5′-phosphate (PLP). Lactobacilli act probiotically by stimulating the immune system, defending against pathogens, and mitigating the impact of various chronic illnesses. To better understand the function and structure of ODC from Lacticaseibacillus rhamnosus (LrODC-WT), we investigated its enzymatic activity, kinetic characteristics, crystal structure, and further examined a variety of single-residue mutants. We found that active LrODC-WT has the following kinetic parameters: K_M 6.83 ± 1.01 mM, k_cat 1.44 ± 0.1 s⁻¹, and k_cat/K_M 210.83 ± 19.37 M⁻¹ s⁻¹. Unlike LrODC-WT, H346A, F186A, H216F, and E281Q showed no catalytic activity. H346A showed maximum unfolding at 2 M guanidine hydrochloride (GdnHCl), while the other enzymes exhibited peak unfolding effects at 1 M, indicating that H346A shows higher resistance to GdnHCl. The PLP binding in LrODCs using a UV/Vis spectrometer showed that LrODC-WT possesses high PLP, while F186A and H346A demonstrated 50% PLP of LrODC-WT, and absent in H216F and E281Q. The crystal structure of LrODC-WT was identified as a tetramer in which PLP was bound to all four subunits and interacted with residue K347 for Schiff base formation. While the crystal structures of H216F and H346A form dimers, an LrODC-WT tetramer can form via hydrogen bonding of D544 and N270. An improved understanding of the structure and function of LrODCs is relevant for controlling its polyamine production and for optimizing L. rhamnosus strains for use as a more potent probiotic.

The cover image depicts a Goldberg machine symbolizing the stereodivergent reaction of α-azaaryl carbonyl derivatives with electrophilic partners (E⁺), producing azaarenes with multiple stereocenters (R,S). By combining a chiral copper Lewis acid with a second chiral catalyst (Ir, Pd, Ni, Ru, or amines) and tuning the stereochemical environment, all possible stereoisomers can be selectively accessed. Details are in the article by Ilwoo Song, Byungjun Kim, Hooseung Lee, and Sarah Yunmi Lee.

As the demand for large-scale energy storage systems increases, so do market expectations for battery performance, especially in electrochemical properties. Against this background, electrode materials with excellent theoretical capacity and unique structures, such as cobalt selenide (CoSe₂), have received significant attention from the research community for their potential in large-scale energy storage systems. These materials exhibit excellent electrochemical properties, including long cycle life, high stability, high energy density, and efficient charge/discharge performance. However, CoSe₂ anode materials still face volume expansion and conductivity degradation in practical applications, affecting battery performance and lifetime. To address these challenges, researchers have proposed a variety of innovative strategies. This paper provides an in-depth evaluation of these strategies and analyzes their potential for practical applications. It is shown that by designing special structural materials, shortening the ion migration path, and increasing the contact area, the electrochemical performance can be effectively enhanced and the performance degradation caused by volume change can be suppressed. With technological advances, it is expected that battery performance will be significantly improved, driving the development of more efficient and environmentally friendly energy solutions.

Extracellular vesicles (EVs) are recently emerged as biomarkers for cancer diagnosis. RNA in EV specifically has drawn attention for its high stability and accuracy for early cancer diagnosis. However, analysis of EV RNA in plasma for cancer diagnosis often can be limited by a low population of cancer-derived EVs in the plasma samples. Herein, we developed a sensitive EV RNA analysis technique with protein-specific EV enrichment for accurate ovarian cancer diagnosis.

Biphenylyl-N-ethylethanamines, novel 5-HT₇R agonists synthesized from 4-chloro-3-iodobenaldehyde, activate the Gs signaling pathway. Among derivatives, compounds 4c and 4f showed potent 5-HT₇R agonism, with EC₅₀ values of 89 and 70 nM, respectively, in cAMP assays. Western blot analysis confirmed dose- and time-dependent ERK phosphorylation, with 4c and 4f inducing sustained pERK expression (14.5- and 11.4-fold at 60 min) compared to 5-HT (4.0-fold), indicating prolonged signaling. Compound 4f exhibited acceptable drug-like properties, including minimal CYP inhibition and moderate microsomal stability. These findings highlight the pharmacological potential of 4f as a 5-HT₇R modulator, warranting further in vivo studies to explore its therapeutic applications.

Aqueous zinc ion batteries (AZIBs) have emerged as a promising next-generation energy storage technology to replace lithium-ion batteries. Recently, gel polymer electrolytes (GPEs), as a critical component of AZIBs, have garnered significant attention due to their potential to address challenges associated with conventional aqueous electrolytes, such as dendrite growth, corrosion, electrolyte evaporation, and leakage. However, the mechanical properties of hydrogels often remain suboptimal due to inherent limitations. This review focuses on the mechanical requirements that GPEs must meet for practical implementation in AZIBs. Furthermore, it highlights various gel design strategies to achieve superior mechanical performance, including double-network (DN) gels, topological gels, and other advanced gel network architectures. Promising directions and rational perspectives for future research are also proposed, offering insights into the development of high-performance GPEs for AZIBs.

Sodium-ion batteries (SIBs) have attracted considerable attention due to their electrochemical similarity to lithium-ion batteries. One approach to advancing the SIB system involves the use of redox-active compounds as sustainable cathode materials. Organic compounds offer the advantage of tunable electrochemical properties, which can be modulated by altering their molecular structures. In this study, the commercially available 2,6-diaminoanthraquinone (2,6-DAAQ) was investigated as a potential cathode material for SIBs. Its sodium-ion storage capabilities were investigated through a combination of electrochemical measurements and density functional theory (DFT) calculations. In addition, the insertion of two Na⁺ ions into the 2,6-DAAQ cathode was analyzed via ex situ ATR FT-IR spectroscopy. The results indicate that the carbonyl groups participate in the redox processes during charge–discharge cycling. The 2,6-DAAQ cathode also exhibited excellent cycling stability and rate capability, which can be attributed to its dominant capacitive behavior. Overall, 2,6-DAAQ demonstrated reversible sodium-ion storage, highlighting its potential as a stable organic cathode for next-generation SIBs.

Cobalt catalysts are emerging as viable alternatives to precious transition metals such as palladium, rhodium, and ruthenium. Compared to rhodium(III) catalysts, cobalt(III) catalysts bearing pentamethylcyclopentadienyl ligands (Cp*) have demonstrated improved reactivity with enhanced chemo- or site-selectivity. Notably, they exhibit robust and sustainable performance in the C–H functionalization of organic substrates, facilitating the synthesis of biologically active molecules. Moreover, this catalytic system is gaining considerable attention for late-stage modifications owing to its cost-effectiveness, sustainability, and lower toxicity. This review highlights recent advancements in Cp*Co(III)-catalyzed C–H functionalization of biologically active scaffolds, including 6-arylpurines, indoles, quinoline N-oxides, and heterocyclic drug molecules.